1. Field of the Invention
The present invention relates to a multi-stable shift-by wire selector control system of a motor vehicle transmission, more specifically an automatic or semi-automatic vehicle transmission and method therefor.
2. Background Art
A shift-by-wire selector having multi-stable positions, each operating a mode of the automatic transmission, i.e. Park, Reverse, Neutral, Drive. The selector may include sensor means for sensing the position of the selector and generating selector signals to a transmission control unit which transmits control signal to the vehicle transmission and an indexing mechanism for maintaining the selector in each of its multi-stable positions. The indexing means has a detent plate having notches for cooperation with a mechanical detent having a configurable force.
Although such a selector has been proven effective, it has been found that it is possible for the selector to be left between two positions, e.g. between a Park position and/or a Neutral position. When this happens, the selector might be able to be moved by a subsequent vibration, shock or even unintentionally by a person and engaged a drive mode (Drive, Reverse) of the automatic transmission even if the selector is left in Park position as the selector cannot be locked by a lock mechanism which can only be engaged when the selector is in a nominal Park position or Neutral position and thus might cause an unsafe vehicle condition.